Bait station and trap

ABSTRACT

A tamper resistant bait station for holding a supply of rodent or other pest bait is disclosed having an outer housing and a tray slidably received within the housing, and is secured in its received position by a tamper-resistant closure. The floor of the housing and the floor of the tray are elevated above the ground and have entrance openings therein in register with one another when the tray is inserted in the housing so that a pest, such as a mouse or rat, may enter the housing and the tray from below via the entrance openings. Partitions within the tray define the various passages and compartments within the tray, these partitions having notches or other openings therethrough to permit the pest to travel from the entrance openings to the bait compartment and to exit the bait station, but yet preventing tampering with the rodent bait and preventing protected wildlife from entering the bait station. The station may be secured to a wall or the like.

BACKGROUND OF THE INVENTION

This invention relates generally to a tamper resistant bait station for holding a supply of toxic pest bait, such as a rodenticide pellet or powder (or other poisonous substance), to be ingested or externally contacted by undesired pests (e.g., mice, rats, snails, or slugs).

For a number of years, it has been conventional, particularly in large commercial buildings, food warehouses, restaurants, farm buildings, schools, and even in human residences, to use a poisonous bait or poisonous tracking powder to poison undesired pests. Even more particularly, in the control of mice and rats, zinc phosphide, and anti-coagulant rodenticides have been widely used. Generally, all such rodenticide baits and bait concentrates approved for use by the U.S. Environmental Protection Agency require labeling to the effect that baits must be placed in tamper proof bait boxes or in locations not accessible to children, pets, domestic animals, or protected wildlife. Further, warnings are given not to place the bait in areas where there is a possibility of contaminating food for human consumption or of contaminating surfaces that come in contact with food. Also, it is highly desirable that powdered baits not be positioned so that it may be disturbed by air currents and thus drawn into ventilation ducts or blown onto food or food contact surfaces.

Prior to and during World War II in England, considerable research was done in regard to bait containers for field use. In 1954, a publication entitled Control of Rats and Mice, pp. 147-159, published by Oxford University Press, London, described two types of bait containers, the first being a specially shaped box in which the bait is inaccessible to animals other than rodents and the other being a blocked drain pipe. The bait box described in the above-identified publication was also disclosed in British Pat. No. 541,844. Generally, this bait box had an enclosed chamber in which the bait was placed with an access opening being provided in the bottom floor defining the chamber so that the rodents may enter the bait box from below. However, it had been noted by the inventors of the above-identified British patent specification that wildlife, such as field sparrows, could enter this prior bait box and gain access to the poisoned bait. Also, because of the design of this prior bait box, it would be possible for a child to reach his hand into the access opening of the bait box and also have direct access to the bait.

Reference may also, be made to such U.S. Pat. Nos. as 794,323, 1,086,610, 1,309,606, 2,299,723, 3,045,387, 3,965,609, 4,208,829, 4,228,613, 4,251,946, which disclose various permanent bait stations for holding a supply of toxic rodent bait or the like. Generally speaking, these prior bait stations have tamper proof access openings or closures, but each of these prior bait stations has certain drawbacks, particularly when considered in light of the more recent U.S. Government Environmental Protection Agency regulations dealing with rodenticide baits.

Still further, such U.S. Pat. Nos. as 3,045,387, 3,298,128, and 4,031,653 disclose various foldable bait stations of fibreboard material, plastic or the like. However, as is intended for these fibreboard bait stations, they do not offer the security required for a permanent bait station and these fiberboard bait stations are intended to be disposed of regularly.

U.S. Pat. No. 4,062,142 discloses a trapping and killing apparatus for mice which traps a live mouse therewithin and which automatically dispenses a quantity of poisonous gas so as to kill any mouse trapped therein.

U.S. Pat. No. 4,251,946 discloses a snail and slug trap wherein the bait is a pesticide which is activated by water contained within a water reservoir.

Lastly, U.S. Pat. No. 4,281,471 discloses a rodent tunnel in the form of an elongate tube so that mice will run through the tube. Cartridges of a suitable contact rodenticide are placed at intervals along the tube such that the mice come into contact with the rodenticide as they travel through the tube and become fatally affected by it.

SUMMARY OF THE INVENTION

Among the several objects and features of the present invention may be noted the provision of a bait station for a powdered rodenticide or the like which may be securely locked in its operative position by means of a low-cost, tamper resistant locking or closure device and yet which may be readily opened for servicing and replenishment of the bait and for removal of dead pests;

The provision of such a bait station which may be readily fastened to a wall or the like of building in position so as to attract mice, rats, or other pests which are desired to be exterminated;

The provision of such a bait station which accommodates the normal feeding instincts of mice and rats thus encouraging them to consume a large portion of their daily diet from the bait station, this being particularly important in the effective treatment of rodents with a multi-dosage and so-called single-dose, anti-coagulant baits;

The provision of such a bait station in which desirably protective wildlife, even field sparrows, are effectively denied access to the bait within the bait station;

The provision of such a bait station which effectively stops movement of air through the bait station which may carry airborne toxic bait or dust out of the bait station;

The provision of such a bait station, when installed in the out-of-doors, effectively shields the bait therewithin from moisture;

The provision of such a bait station which is of such a design so as to positively prevent the fingers of either an adult or child from physically coming in contact with the bait within the main bait compartment of the bait station so long as the bait station is in its installed position;

The provision of such a bait station which is constructed as to provide a familiar surface, such as bare ground, rock, asphalt, or concrete, as the beginning of a darkened entrance tunnel leading to a multi-plane maze in the darkened interior thereby to encourage rodents and to give them the security to enter and remain in the bait station and to feed on the bait;

The provision of such a bait station which is so constructed as to provide a darkened entrance tunnel, and darkened interior thereof, thereby to encourage rodents and to give them the security to enter and remain in the bait station and to feed on the bait; and

The provision of such a bait station which is of low cost, which is of rugged construction, which has a long service life, and which is in compliance with existing U.S. Government Environmental Protection Agency regulations relating to toxic rodenticides and the like.

Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the bait station of the present invention illustrating a housing and a compartmentized tray which slides horizontally into the housing between a disassembled position (as shown in FIG. 1) and an installed position (not shown) in which the tray is received in the housing, with portions of the housing broken away to illustrate details of construction;

FIG. 2 is a side elevational view of FIG. 1, again with portions of the housing and the tray broken away to illustrate details of construction with the back wall of the housing installed against the wall of a building (shown in phantom) and with the housing resting on the floor of the building (also shown in phantom);

FIG. 3 is an end elevational view of the housing taken along line 3--3 of FIG. 2;

FIG. 4 is an end elevational view of the tray taken along line 4--4 of FIG. 2;

FIG. 5 is a vertical cross-sectional view taken along line 5--5 of FIG. 1 on an enlarged scale illustrating a tamper-resistant fastener utilized to secure the tray within its installed position within the housing;

FIG. 6 is a plan view of a large food warehouse showing the locations of twenty-four bait stations of the present invention in a side-by-side comparison with prior bait stations; and

FIG. 7 is a graph comparing the effectiveness of the bait station of the present invention with prior bait stations in three different field tests.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the drawings, a bait station, as generally indicated by reference character 1, is shown to comprise a housing 3 and a tray 5 with the tray being slidable in horizontal direction between a removed position (as shown in FIG. 1) in which the tray is clear of the housing and an installed position (not shown) in which the tray is received within the housing.

Referring now to housing 3, it includes a support or floor 7 having a pair of opposed housing sidewalls 9a, 9b extending upwardly from the floor at the opposite sides thereof. A back housing wall 11 extends up from the floor 7 between sidewalls 9a, 9b, and a top 13 bears against the upper edges of the side and back walls and is secured or bonded thereto so as to form a substantially rectangular, sealed opening or cavity therewithin having an open front for receiving tray 5. Housing top 13 has an overhang 14 which extends out beyond the front edge of floor 7. As shown best in FIGS. 2 and 3 and as indicated at 15a, 15b, sidewalls 9a, 9b extend down below the level of housing floor 7 for supporting housing 3 on the floor F of a building or the like. Still further, in accordance with this invention, the housing floor 7 has an access opening 17 therein, this access opening being shown to be located adjacent the front edge of the floor and offset to one side of the housing, as best illustrated in FIG. 1. However, it will be understood, that within the broader aspects of this invention, opening 17 may be located at any desired location on floor 7.

Tray 5 is shown to comprise an open top, boxlike structure having a tray floor 19 with opposite tray sides 21a, 21b and a tray end or backwall 23 sealingly secured to and extending up from the tray floor. The back wall 23 is preferably sloped at an angle of about 5° (as shown in FIG. 2) to compensate for the wall securing device in the housing. The width of the tray floor and the height of the side and endwalls of the tray is such that the tray 5 is readily received within the open front of housing 3 so that it may be readily slid into and out of the housing. Still further, tray 5 has a front end wall 25 at the end thereof opposite the backwall and this front tray wall has a tray ledge 27 extending horizontally, outwardly from the upper edge of the tray front wall such that with the tray received within the housing, the tray ledge 27 is disposed below in close proximity to the housing top overhang 14, as best shown in FIG. 5. The front of tray ledge 27 may slope downwardly to direct moisture away from the interior of the bait station. Further, tray front wall 25 has an extension or leg, as indicated at 29, which extends down below tray floor 19 and which, together with housing side extensions 15a, 15b, constitute the legs or supports for the bait station when the tray is inserted into the housing in its installed position. At each side of housing 3, notches N are provided. Tray 5 has side flanges F which are received in notches N and aid in enabling one to grip the tray for removal from the housing. Further, a finger grip FG may be provided on tray front wall 25 to permit removal of the tray. The inner face of housing top 13 has a pair of spaced rails R1 extending lengthwise therewithin. Grooves G are provided in the upper edge of tray back wall 23 to cooperate with rails R1 and to aid in guiding of the tray as it is slid in and out of the housing. Also, these cooperating rails R1 and grooves G inhibit moisture from entering the bait station and prevent dust from bait B from escaping.

Still further, tray floor 19 is provided with a tray access opening 31 (see FIG. 1) generally in register with housing access opening 17 when the tray is inserted into the housing in its installed position. In this manner, a pest, such as a mouse or the like, on building floor F may readily enter the housing and the tray from a tunnel T below housing floor 7 via housing access opening 17 and via tray access opening 31 from below. The pest or mouse enters the tray through access opening 31, and moves into a so-called entry passage 33 defined by a first partition 35, portions of tray sidewalls 21a, 21b, and by tray front wall 25. The remainder of the interior of tray 5 is further divided by a second partition 37 into a bait compartment 39 and into a so-called intermediate compartment 41. As indicated at B, a suitable bait, such as a rodenticide or the like, which is attractive to the pest, is placed within bait compartment 39. The intermediate compartment 41 is divided by a low partition 42 which aids in preventing the loose bait B from being kicked out of the tray by the pests and which also prevents the pests from caching particles of bait.

With the pest (e.g., a mouse) having entered entry passage 33 via the access openings 17 and 31, the pest will smell or sense the bait and be attracted thereto. To permit passage of the pest from entry passage 33 into the bait compartment 39, a first opening or notch 43 is provided in partition 35 thereby to permit the pest to travel from entry passage 33 into the intermediate chamber 41. As best shown in FIG. 4, this first opening 43 is defined by a first threshold 45 provided in partition 35 which is spaced somewhat above the level of tray floor 19, but yet which provides a sufficient space between the upper surface of threshold 45 and the inner surface of housing top 13 so as to permit the mouse (or other pest) to travel up over the threshold 45 and into intermediate chamber 41. Optionally, a hinged door 44 may be provided on the inside of intermediate compartment 41 adjacent opening 43 to still further aid in containing the loose bait. Door 44 is hinged at its top and is normally closed, but the door is readily opened by a pest entering chamber 41 from entrance 33. It will be understood that door 44 may extend below threshold 45 so that the door 44 may not be opened by a pest within chamber 41. Thus, the bait station 1 may also serve as a trap.

Likewise, a second opening or notch 47 is provided in the second partition 37 to permit the mouse within chamber 41 to pass back and forth from the intermediate chamber into the bait compartment 39. This second notch 47 is defined by second threshold 49 in partition 37 and, like threshold 45, threshold 49 is spaced above the level of tray floor 19, but yet is spaced below housing top 13 a sufficient distance so as to permit the mouse to have ready access to the bait compartment.

While it will be understood that the dimensions of bait station 1 of the present invention may be varied considerably, depending on the particular type of pest (e.g., a mouse, a rat, snails, slugs, or the like) to be baited, the dimensions of the housing, the tray, and the access openings 17 and 31 in the housing and the tray should be sized so that the desired pests may readily enter the bait station, may readily travel from one compartment to another via the openings 43 and 47 and yet will effectively prevent certain kinds of protected wildlife and children or adults from entering the bait station via the access openings and gaining access to the bait B in bait compartment 39.

For example, if bait station 1 is intended to serve as a bait station for house mice or the like, housing 1 may have a width of approximately 3.4 inches (8.6 cm.) and a length along its side (not including top overhang 14) of approximately 4.75 inches (12.0 cm.). As mentioned, tray 5 is dimensioned so as to readily slide into and out of the interior of housing 3 and may, for example, have a height of 2.0 inches (5.1 cm.). Further, side housing wall extensions 15a, 15b and front tray wall extension 29 constituting the legs of the bait station, may have a length extending below floor 7 of housing 13 of approximately 1 inch (2.54 cm.) so as to form tunnel T beneath the lower surface of housing bottom wall or floor 7. Housing wall extensions 15a, 15b may have tapered blocks 58a, 58b on the inside faces thereof so as to reinforce the wall extensions and to provide a smaller cross section into tunnel T so that the darkened tunnel will not be attractive to other forms of wildlife. Additionally, the dimensions of access openings 17 and 31 in housing floor 7 and tray floor 19, respectively, are approximately 1.5 inches (3.8 cm.) by 1.0 inches (2.54 cm.) so as to permit a mouse to readily enter the bait station from below. These dimensions are such as to permit a mouse to readily enter the bait station via the access openings but yet, in a manner as will be more specifically pointed out hereinafter, effectively prevent other larger animals, such as field sparrows, dogs, and the like from having access to the bait within the bait station. Moreover, it has been determined that the above-mentioned size for the access openings 17 and 31 will permit a variety of smaller pests, such as house mice, whitefooted deer mice, large cockroaches, garden slugs and snails to enter the bait station. This size opening was selected taking the size and habits of a full-grown house mouse into account. It will be appreciated that the eyesight of a mouse is not good and that a mouse finds its food primarily through its sense of smell. A mouse is accustomed to moving freely in darkened, cramped quarters and depends on sensory hairs along its back, ears, face, and sides plus it vibrissae (or whiskers) to guide the animal safely. The above-mentioned size of the access openings 17 and 31 and the size of bait station 1 is such that a typical mouse will freely enter the bait station and will be guided through the openings in the various baffles to bait B in bait station 39. It has been found that if the dimensions of the bait station are appreciably smaller than above indicated, mice will have a tendency not to enter the bait station because of undue contact with the access opening and the sides of the compartment with the mouses's vibrissae. However, the size of the access openings has been kept to a minimum so that other wildlife and domestic pets will not have ready access to bait B within the bait station.

Further in accordance with this invention, bait station 1 is intended to be substantially tamper resistant so as to prevent small children or the like from removing tray 5 from within housing 3 so as to have access to the bait B within bait chamber 39. This tamper resistant feature may be accommodated in any number of manners including the provision of a key and lock mechanism (not shown) so as to securely fasten the tray within the housing. However, because of the expense of a key and lock system, effective tamper resistance may be provided by securing the tray within the housing by means of a selectively actuable locking fastener means, as generally indicated at 51, as best illustrated in FIG. 5. More specifically, an aperture 53 is provided in top overhang 14 of housing top 13 and this last mentioned aperture is in register with another aperture 55 provided in tray ledge 27 when the tray is fully received in its installed position within the housing. A locking fastener 57 may be inserted through the apertures 53 and 55 and threadably extends into a housing 58 which hides fastener 57. It will be appreciated that any number of conventional tamper resistant fasteners may be utilized to prevent unauthorized entry into the bait station. For example, fastener 57 may be a special screw having a special spanner head which does not have a conventional drive slot. A modified screwdriver must then be utilized as the drive tool so as to install and remove the fastener from housing 58. Additionally, a variety of proprietary fastener heads are available from different manufacturers which also require specialized drive tools for installation and removal.

As best in FIG. 2, housing 3 is primarily intended to be mounted within a building along a wall W of the building with the back face 11 of the housing in flush engagement with the wall and with the bottom ends of side extensions 15a, 15b and the bottom of tray front wall extension bearing on building floor F. More specifically, fastener means, as indicated at 59, may be inserted through slots 61 for threadably securing the bait station housing to wall W of the building. As shown in FIG. 2, fastener means 59 may be constituted by a conventional wood screw or the like. It will be appreciated that with the dimensions of housing 3 as generally outlined above, it is a relatively easy matter to install screws 59 in holes 61 in the back wall 11 of the housing and to securely mount the housing to wall W. Those skilled in the art will appreciate that the housing may be secured to the floor or wall by any suitable fastening means, such as bolts, clamps or adhesive tapes. For example, back wall 23 may be adhered to a board (not shown) which in turn may be secured to a building wall.

It will further be appreciated that with the back wall of the housing mounted to wall W and with the bottoms of housing side extensions 15a and 15b and with the bottom of front tray wall extension 29 bearing on the floor F, the bottom wall 7 of housing 3 is raised above the floor F approximately 1 inch and thus a runway, as indicated at R in FIG. 2, is formed by wall W, the floor F, and the notched portions in the housing side wall extensions 15a, 15b. It is conventional for pests, such as mice, to travel in close proximity to the intersection of the wall W and the floor F of the building and thus mice would have a strong tendency to travel through runway R of bait station 1. As the mice travel through the runway R, they come in close proximity to bait B which is relatively easy for them to smell. Then, the tunnel T defined by the sidewall extensions 15a, 15b and by the front wall extension 29 provide a ready path which the mouse is likely to explore. The fact that tunnel T is the same level as floor F and is a part of the floor having the same feel as the floor gives the mouse confidence to enter the tunnel. It is a natural tendency for a mouse or other rodent, when in a cramped, dark enclosure, such as tunnel T, to feel upwardly as well as to the sides and thus the mouse is quite likely to find the upward access openings 17 and 31. Then, drawn by the odor of bait B in bait compartment 39, the mouse will enter compartments 33 and 41, and finally bait compartment 39. Because of the dark secure nature of the bait station, the mouse will have a tendency to feel secure within the bait station and thus is likely to feed on bait B for a considerable length of time. The multi-plane surfaces of the ground in tunnel T, of floor 19, and of the various partitions 35, 37, and 43 form a maze leading to bait compartment 39 which is conducive to rodents remaining in the bait station. Moreover, because the bait stations are at least semi-permanent fixtures installed within the building and may be present for a length of time, the mouse will likely return to the bait station for subsequent feedings of the bait when repeated dosages of the bait are required to be effective.

It will also be appreciated that with the bait station 1 of the present invention secured to wall W by screw 63 as above described, the bait station of the present invention is rendered even more tamper resistant to small children or the like. More specifically, with the tray 5 securely fastened within the housing 3 by means of tamper resistant fastener means 51, as heretofore described, a child must attempt to reach his finger into tunnel T from below via the runway R. Further, it would be necessary for the child to reach his finger up through access openings 17 and 31, through the entrance passageway 33, through the first access notch 43 in the first partition 35, through the intermediate compartment 41, through the second notch 47 and into the bait compartment 39. Also, because of the circuitous path that small animals must traverse to the bait compartment 39, only nocturnal, inquisitive rodents generally of the size of the desired pest (e.g., a house mouse or the like) would be likely to enter the bait station. Thus, even if the bait station were proportionately scaled up in size so as to be effective against rats, domestic cats and the like would be unlikely to enter runway R, tunnel T and follow the above-described path through the bait station to the bait B.

It will also be appreciated that when the bait stations 1 of the present invention are installed in a large commercial building, such as a food warehouse, barn or the like, it is necessary to periodically clean the bait stations and to replenish the supply of bait B. This may be readily done by utilizing a special tool so as to remove tamper resistant fastener means 51 thereby to permit tray 5 to be withdrawn from housing 3. The debris within the tray including the old supply of bait B may then safely be disposed of by dumping the tray into a suitable container and the supply of bait B may be replenished within the bait chamber 39. The tray may then be reinserted into the housing and the tamper resistant fastening means may then be reinserted in apertures 53 and 55. Thus, the periodic servicing of the bait stations may be accomplished within a matter of less than a minute or so, this being extremely important realizing that there may be several dozen of the bait stations strategically located throughout a large warehouse or barn.

It will also be appreciated that because of top overhang 14 and because of the tray front wall extension 29, and further because of the sealed joints between all of the walls of the housing and the tray, and further, because of the bottom access opening 17 and 31, the bait within the bait station is adequately protected from the rain and the wind thus serving to prevent the bait from degrading due to exposure to the elements and also effectively preventing dried baits or powders from being blown by the wind and scattered throughout the warehouse, possibly coming in contact with food or being drawn into ventilating ducts or the like.

While one particular design of the bait station of this invention has been disclosed wherein the housing and the tray are generally of rectangular shape, it will be appreciated that other configurations or shapes of the bait station 1 of the present invention could be readily used while employing the same inventive features of the present invention utilizing bottom access openings, runways R, tunnels T, entrance passageways 33, intermediate passages 41, a bait compartment 39 with baffles formed by thresholds 45 and 47 through the partition leading from one compartment to another. More specifically, it will be understood that the number of partitions within the tray 5 may be varied and the location of the openings may be changed and yet the bait station may still be within the broad inventive concept of the present invention.

In order for the bait station 1 of the present invention to be effective in eradicating mice, rats, or other pests, it is important that the pests utilize the bait station for a major portion of the food consumed by the pests, particularly where multi-dosage, anti-coagulant rodenticides are utilized. To compare the effectiveness of the bait station 1 of the present invention with a standard so-called Eaton or NBS mouse station, this Eaton mouse station being described in National Bureau of Standards publications, some twenty-four bait stations 1 of the present invention were installed on the exterior of a large food warehouse in side-by-side relation with the prior art NBS stations with the stations spaced 3 inches apart and with each of the bait stations being charged with equal, predetermined amounts of the identical bait. The NBS station is a box with side entry, a partial divider therein, and for separating the entry chamber from the bait holding chamber. In FIG. 6, the locations of these dual bait station locations are shown by the circled numbers. Then, over a period of time, the bait stations were periodically checked and the amount of bait consumed from both the bait station 1 of the present invention and the prior art standard bait station at the same location were compared.

In conducting the field tests, it will be appreciated that a number of test stations are required to take into account the fact that at certain locations, mouse feeding may be particularly heavy while at other stations, mice may not frequent the bait stations during the test period. Also, it will be appreciated that at some locations, considerably more food may be consumed in one bait station than the other (i.e., more food consumed in the prior art bait station than in the bait station 1 of the present invention or vice versa). However, on the average, considerably more bait was consumed in the bait stations 1 of the present invention than in the adjacent prior art bait station. This increased consumption is shown graphically in FIG. 7 by presenting the comparative feeding test results of 3 field experiments in which bait station 1 of the present invention were installed in side-by-side relation with the above-described prior art NBS bait stations. In the first field test, approximately 98% of the bait consumed during the field test was consumed within bait stations 1 of the present invention while only 2% of the bait consumed was in the prior art bait stations. In the second and third field tests, the amount of bait consumed in the bait stations 1 of the present invention was approximately 84% and 87%, respectively. Thus, it is readily seen that the effectiveness of the bait stations 1 of the present invention is several times greater than the prior art bait stations in inducing the pests to eat the bait on a consistent, repeated basis.

While housing 3 was described as having a continuous tray support floor 7 with access opening 17 therein, it will be understood that the tray support may consist of ledges or shoulders (not shown) secured to each wall 9a, 9b of the housing so that tray 5 will be supported thereon. Other tray support structures are within the broader aspects of this invention.

In view of the above, it will be seen that the other objects of this invention are achieved and other advantageous results obtained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense. 

What is claimed is:
 1. A bait station or trap comprising an open front housing and a tray insertable into said housing in the open front of the housing, said housing having means for supporting it above the surface on which it rests, said tray having a floor and partition means thereon defining an entrance chamber, a bait chamber, and a circuitous path between said entrance chamber and said bait chamber, said tray floor having an access opening therethrough in register with said entrance chamber wherein a pest must enter said bait station from below said tray floor and must travel said circuitous path from said entrance chamber to said bait chamber.
 2. A bait station for holding a supply of toxic pest bait, the station including a housing and a tray slidably received within said housing and being movable relative to said housing between an extended position in which said tray is clear of said housing for access to said tray and an installed position in which said tray is received within said housing, said housing having a support for said tray, a sidewall at each side of said support and extending upwardly therefrom, a backwall at the back of said support and extending upwardly from the support, a top overlying said support and mating with the upper edges of said side and back walls, said housing sidewalls extending downwardly below said floor for supporting said housing in a position elevated above the surface on which said sidewalls rest so that a pest may enter said housing from below, said tray having a tray floor, a tray sidewall extending up from each side of tray floor, a tray backwall extending up from the back of said tray floor, and a tray front wall extending up from the front of said tray floor, said tray side, back, and front walls being of substantially similar height with the height of said tray being somewhat less than the height of said housing between the upper faces of said support and said housing top such that said tray may be readily inserted in and withdrawn from the open front of said housing, said tray having one or more partitions therein cooperable with said tray side walls and with said tray floor so as to define an entry passage and a bait compartment, the portion of said tray floor constituting a portion of said entry passage having an access opening therethrough thereby to permit entry of the pest into the entry passage of the tray from below, said partitions having an opening therethrough so as to permit access of the pest from said entry passage to said bait compartment.
 3. A bait station as set forth in claim 2 wherein said tray support in said housing is a floor, said housing floor having an opening therethrough in register with said access opening in said tray floor when said tray is in its installed position.
 4. A bait station as set forth in claim 2 further comprising tamper-resistant securement means for locking said tray in its installed position within said housing.
 5. A bait station as set forth in claim 2 wherein the bait station further includes means for securing said housing to a building or other permanent structure.
 6. A bait station as set forth in claim 5 wherein said securing means is a threaded fastener inserted through an opening in the back wall of said housing and engagable with said wall.
 7. A bait station as set forth in claim 2 wherein said sidewalls of said housing and said front wall of said tray extend down below the level of the floor of said housing such that the bottom edges thereof are generally coplanar, said housing sidewall extensions and said front tray wall extension constituting legs for supporting the bait station in a raised position above the level of the surface on which the bait station rests.
 8. In a bait station as set forth in claim 7 in which the ends of the housing sidewall extensions adjacent the back wall of the housing are notched so as to define a runway beneath the housing floor adjacent against the wall on which the bait station is installed.
 9. A bait station as set forth in claim 8 in said access opening in said housing floor is located adjacent the front of said housing a distance from said runway with the extensions of said housing sidewalls and said tray front wall constituting a tunnel leading from said runway to said access opening.
 10. A bait station as set forth in claim 2 wherein said housing top has an extension extending out beyond the front of the housing, and wherein said front tray wall has a ledge extending generally horizontally outwardly from the top of said tray front wall with said housing top extension and said tray front ledge having apertures therethrough in register with one another when said tray is inserted in said housing, said tamper resistant means comprising a tamper resistant fastener inserted through said apertures thereby to positively lock said tray in its installed position within said housing.
 11. A bait station as set forth in claim 2 wherein said housing top has at least one rail on its inner face extending lengthwise of the housing, and a groove in the upper edges of said tray cooperable with said rail as said tray is moved in and out of said housing. 